Silicon ingots may be grown by the so-called Czochralski process in which a silicon ingot is pulled upward from a melt of silicon in a crystal puller apparatus. The process may be a continuous process in which silicon is intermittently or continuously added to the crucible as polycrystalline chunks or as pre-melted silicon or may be a batch process in which the ingot is withdrawn until silicon within the crucible is consumed.
Crystal pulling may be performed in the presence of an atmosphere within a housing of the puller. In both batch and continuous Czochralski processes, a process gas inert relative to silicon such as argon is continually introduced into the housing and withdrawn through an exhaust system of the puller. As the process gas is withdrawn, compounds may deposit on the exhaust system piping which is at a lower temperature compared to the puller chamber. Such deposits are removed from the system which may require the puller to be taken out of operation thereby increasing processing cost.
A need exits for methods for producing silicon ingots that are characterized by reduced formation of deposits on the exhaust system of the puller.
This section is intended to introduce the reader to various aspects of art that may be related to various aspects of the disclosure, which are described and/or claimed below. This discussion is believed to be helpful in providing the reader with background information to facilitate a better understanding of the various aspects of the present disclosure. Accordingly, it should be understood that these statements are to be read in this light, and not as admissions of prior art.